The subject matter disclosed herein relates to nuclear imaging, and more particularly to correction of artifacts caused by out-of-field source in nuclear imaging techniques, such as single photon emission computed tomography (SPECT) or other emission based tomography approaches.
A variety of imaging techniques are known and currently in use, such as for medical diagnostic applications. Certain such techniques, such as SPECT, rely on the emission of gamma rays during the radioactive decay of a radioisotope (or radionuclide), commonly administered in the form of a radiopharmaceutical agent that can be carried by, and in some cases, bound to particular tissues of interest. Such nuclear imaging technologies detect the emissions via a suitable gamma radiation detector. In particular, a suitable gamma radiation detector may consist of components which, in response to incident radiation, generate image data related to the quantity of radiation impacting the individual regions of the detector. The image data generated by the detector components may then be reconstructed to generate images of internal structures of the subject.
While such systems have proven extremely useful at providing high quality images with good diagnostic value, further refinement is possible. For example, in some instances, a particular portion of a patient's anatomy may be of interest to a clinician. In such instances, the clinician may attempt to obtain image data related to the organ of interest. However, due to the manner in which data is collected, typically from a large number of views or angles about the patient, certain of the collected data may include data that represents not only the region of interest to the clinician, but other portions of the patient anatomy that may not be of interest. For example, other organs or regions of the patient may participate in the breakdown of the radiopharmaceutical agent and may thus emit gamma rays beyond the background level otherwise observed. To the extent that these other organs or regions are visible in the image data collected at certain views, the quality of the images generated for the actual region of interest may be impacted. This effect may be present in small field of view cameras where the size of the imaging detectors is limited and with cameras where the detectors are specifically aimed at the organ of interest. Similarly, the difficulty may be present in PET (Positron Emission Tomography) when using a detector which is not a full circle.